Taxonomy and palaeoecology of Cretaceous nautilids Angulithes galea (Fritsch in Fritsch & Schlonback, 1872 and Angulithes wesphalicus (Schulter, 1872)
Abstract
Angulithes galea (Fritsch in Fritsch & Schlönbach, 1872) and Angulithes westphalicus (Schülter, 1872) are representatives of Angulithes Montfort, 1808, occurring in the Late Cretaceous of Europe, from the Late Turonian to the Late Campanian. Following examination of the majority of specimens representing these species and their specific morphology, a detailed revision was made.
Both species undergo significant morphological changes during their ontogeny, changing the shape of the ventral side and whorl cross-section attended by onset and loss of ventral keel and changing of the shell surface (by A. galea). Comparing these changes with the ontogeny of recent Nautilus suggests they are expressions of the approach and attainment of maturity.
Due to this comparison, comparable changes in other taxa can be similarly interpreted, e.g. representatives of the genus Deltocymatoceras.